How to fix Container exited with status code 2 in Docker

First, examine the container logs to see what command failed and why:

docker logs <container_name_or_id>

Look for error messages like "syntax error", "missing argument", "invalid option", or usage help text that indicates incorrect command invocation.

Start the container with an interactive shell to manually test commands:

docker run -it --entrypoint /bin/sh <image_name>

Once inside, try running the commands from your Dockerfile or entrypoint script manually to identify which one fails.

A common cause is missing files. Check that your scripts and referenced files exist:

# Inside the container
ls -la /app/
cat /app/entrypoint.sh

If using WORKDIR, ensure the directory exists and contains your files. Volume mounts can overwrite directories, hiding files copied during build.

Validate your shell scripts for syntax errors before building:

# Check bash script syntax
bash -n your-script.sh

# Check sh script syntax
sh -n your-script.sh

Common issues include:
- Missing closing brackets in conditionals: [ -f file ] not [ -f file
- Unclosed quotes or missing spaces around brackets
- Using bash-specific syntax in /bin/sh scripts

Ensure your Dockerfile uses the correct format for CMD and ENTRYPOINT:

# Exec form (recommended) - runs command directly
CMD ["python", "app.py"]

# Shell form - runs through /bin/sh -c
CMD python app.py

If using exec form, ensure it's valid JSON. A malformed array like CMD ["python" "app.py"] (missing comma) will cause parsing errors.

If developing on Windows, shell scripts may have CRLF line endings that cause parsing errors:

# Convert to Unix line endings
dos2unix your-script.sh

# Or in Dockerfile
RUN sed -i 's/\r$//' /app/entrypoint.sh

You can also configure Git to handle line endings:

git config --global core.autocrlf input

Enable verbose output to see exactly which command fails:

# Temporarily add -x flag for debugging
CMD ["/bin/sh", "-x", "/app/entrypoint.sh"]

Or add set -x at the top of your shell script. This prints each command before execution, making it easy to identify the failing line.

Commands may fail if required environment variables are missing:

# Check environment in container
docker run --rm <image_name> env

# Or inspect a running container
docker exec <container_id> env

Ensure variables referenced in scripts are defined in your Dockerfile or docker-compose.yml.